comparison setup.py @ 32782:9a4adc76c88a

setup: avoid linker warnings on Windows about multiple export specifications

The PyMODINIT_FUNC macro contains __declspec(dllexport), and then the build
process adds an "/EXPORT func" to the command line.  The 64-bit linker flags
this [1].

Everything except zstd.c and bser.c are covered by redefining the macro in
util.h [2].  These modules aren't built with util.h in the #include path, so the
redefining hack would have to be open coded two more times.

After seeing that extra_linker_flags didn't work, I couldn't find anything
authoritative indicating why, though I did see an offhand comment on SO that
CFLAGS is also ignored on Windows.  I also don't fully understand the
interaction between msvccompiler and msvc9compiler- I first subclassed the
latter, but it isn't used when building with VS2008.

I know the camelcase naming isn't the standard, but the HackedMingw32CCompiler
class above it was introduced 5 years ago (and I think the current style was
in place by then), so I assume that there's some reason for it.

[1] https://support.microsoft.com/en-us/help/835326/you-receive-an-lnk4197-error-in-the-64-bit-version-of-the-visual-c-compiler
[2] https://bugs.python.org/issue9709#msg120859

32781:448fc659a430

    # the cygwinccompiler package is not available on some Python
    # distributions like the ones from the optware project for Synology
    # DiskStation boxes
    class HackedMingw32CCompiler(object):
        pass

packagedata = {'mercurial': ['locale/*/LC_MESSAGES/hg.mo',
                             'help/*.txt',
                             'help/internals/*.txt',
                             'default.d/*.rc',

32782:9a4adc76c88a

    # the cygwinccompiler package is not available on some Python
    # distributions like the ones from the optware project for Synology
    # DiskStation boxes
    class HackedMingw32CCompiler(object):
        pass

if os.name == 'nt':
    # Allow compiler/linker flags to be added to Visual Studio builds.  Passing
    # extra_link_args to distutils.extensions.Extension() doesn't have any
    # effect.
    from distutils import msvccompiler

    compiler = msvccompiler.MSVCCompiler

    class HackedMSVCCompiler(msvccompiler.MSVCCompiler):
        def initialize(self):
            compiler.initialize(self)
            # "warning LNK4197: export 'func' specified multiple times"
            self.ldflags_shared.append('/ignore:4197')
            self.ldflags_shared_debug.append('/ignore:4197')

    msvccompiler.MSVCCompiler = HackedMSVCCompiler

packagedata = {'mercurial': ['locale/*/LC_MESSAGES/hg.mo',
                             'help/*.txt',
                             'help/internals/*.txt',
                             'default.d/*.rc',